February 28, 2017 admin

Stream Buffers

Water Quality, Soil Health Solutions: Stream Buffers

Stream Buffers: Buffers are grassy or native vegetation adjacent to streams that trap sediment from surface runoff. This reduces phosphorus entering a waterway, filters nitrogen as it moves in groundwater through the soil, stabilizes stream banks and provides habitat for wildlife.

There are several different words used for the same practice: stream buffers, riparian buffer strips and filter strips. ‘Stream buffers’ are used here. Stream buffer strips are areas surrounding water sources that have been taken out of agricultural production. These areas are then planted with a variety of grasses, shrubs and/or trees that help improve water quality. The primary benefit of stream buffer strips is to trap soil and phosphorus in surface runoff before it reaches a stream or river.

For stream buffers to be effective without excessive maintenance, soil erosion must be well controlled on the land draining toward the stream buffer. A uniform buffer is preferred by many producers, but varying the width of the stream buffer based on the amount of runoff that enters each section is more effective.

Click on one of the icons below to learn more about 14 key practices being implemented across Iowa to improve water quality.

Cover Crops Various crops grown between the harvest of row crops, like corn or soybeans and planting of the following year’s row crop to cover the soil, reduce nitrogen loss through plant uptake and phosphorus loss through reduced erosion.

Watershed Planning Watershed planning: Farmers, stakeholders, and experts collaborate to create watershed plans. This helps communities identify and understand specific actions that could result in improved water quality.

Bioreactors Redirects tile water to an underground bed of wood chips where nitrate is removed naturally by microorganisms. Vegetation on top of the bioreactor can provide other benefits such as wildlife habitat.

Saturated Buffers A water level control structure is installed near the outlet of a tile line, but within or immediately adjacent to an existing stream buffer. A portion of the water is diverted into a tile line parallel to the stream and within the buffer. Excess nitrate in the tile flow is converted to harmless nitrogen gas in the soil of the stream buffer due to organic matter and low oxygen.

Wetlands A shallow vegetated pool that helps filter nutrients, especially nitrate, control flooding and provide wildlife habitat.

Drainage Water Management Use of a control structure to manage drainage of water from fields throughout the year. The practice reduces the loss of nitrate and can increase crop yields in some years. Also called controlled drainage.

Extended Crop Rotation A planting cycle of different crops such as grasses, legumes or small grains along with corn and soybeans to help improve soil health and decrease insect and disease pressure. The practice can help improve water quality by extending the number of months the soil is covered with actively growing plants.

No Till Strip Till Icons

No Till/Strip Till No-till farming greatly reduces soil disturbance, which in turn reduces soil erosion, builds soil organic matter and helps reduce phosphorus entering waterways.

Nutrient Stewardship The fertilizer rate, timing, placement and the form of nutrients applied are managed to maximize the nutrients that are taken up by the crop while minimizing the loss of nutrients to surface water, groundwater or to the atmosphere. The nutrients of greatest interest in Iowa are nitrogen and phosphorus.

Prairie Strips Buffer strips of native prairie grasses are placed on the contour in crop fields, combined with filter strips of prairie grass strategically placed where runoff leaves the field. This practice results in large improvements in runoff water quality with only a small (~10%) portion of the field taken out of row crop production.

Stream Buffers Buffers are grassy or native vegetation adjacent to streams that trap sediment from surface runoff. This reduces phosphorus entering a waterway, filters nitrogen as it moves in groundwater through the soil, stabilizes stream banks and provides habitat for wildlife.

Grassed Waterway Grassed waterways are shaped constructed channels that are seeded to grass or other suitable vegetation to slow and carry water to a suitable outlet and prevent gulley erosion.

Terraces An earthen embankment constructed across a field slope, breaking long slopes into shorter ones. Terraces slow and or hold water.

Water and Sediment Control Basins An earth embankment or a combination ridge and channel constructed across the slope of minor watercourses to form a sediment trap and water detention basin with a stable outlet.